Ultra-high-resolution observations of persistent null-point reconnection in the solar corona

• Published in: Nature communications Vol. 14; no. 1; pp. 2107 - 10
• Main Authors: Cheng, X., Priest, E. R., Li, H. T., Chen, J., Aulanier, G., Chitta, L. P., Wang, Y. L., Peter, H., Zhu, X. S., Xing, C., Ding, M. D., Solanki, S. K., Berghmans, D., Teriaca, L., Aznar Cuadrado, R., Zhukov, A. N., Guo, Y., Long, D., Harra, L., Smith, P. J., Rodriguez, L., Verbeeck, C., Barczynski, K., Parenti, S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.04.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/33/525/870; 639/766/1960/1134; Astrophysics; Average velocity; Corona; Eruptions; Extreme ultraviolet radiation; Heat; High resolution; High temperature; High temperature plasmas; Humanities and Social Sciences; Laboratories; Magnetic fields; multidisciplinary; Polarity; Science; Science (multidisciplinary); Sciences of the Universe; Solar and Stellar Astrophysics; Solar corona; Solar Orbiter (ESA); Solar physics; Spacecraft; Spine; Sun; Sunspots; Ultraviolet imagery
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-37888-w

Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km s −1 and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona. Magnetic reconnection is a fundamental energy release mechanism in space and laboratory plasmas. Here, the authors show persistent magnetic null-point reconnection in the solar corona at a scale of about 390 km.